Isoket (Isosorbide Dinitrate)

Isoket (isosorbide dinitrate) belongs to the nitrate vasodilator class and is employed to manage cardiovascular conditions that involve myocardial oxygen demand.

• Angina pectoris: reduces frequency and severity of chest pain by dilating coronary arteries.
• Heart failure: improves cardiac output by decreasing preload and afterload.
• Prophylaxis of angina attacks during exertion: provides preventive relief for patients with known coronary artery disease.

• Isosorbide dinitrate releases nitric oxide in vascular smooth muscle, activating soluble guanylate cyclase and increasing cyclic GMP levels. Elevated cGMP leads to relaxation of smooth muscle cells, causing vasodilation of veins and arteries, which lowers cardiac preload and afterload and reduces myocardial oxygen consumption.

Isoket may cause a range of adverse reactions, which are categorized by frequency.

Common Side Effects

• Headache: throbbing pain often occurring shortly after administration.
• Hypotension: noticeable drop in blood pressure, sometimes accompanied by dizziness.
• Flushing: warm sensation and reddening of the skin.
• Dizziness or light‑headedness: especially when standing quickly.
• Nausea: mild gastrointestinal upset.
• Tachycardia: compensatory increase in heart rate.

Serious or Rare Side Effects

• Severe hypotension: can lead to syncope or shock.
• Myocardial infarction: rare but possible in susceptible patients.
• Life‑threatening arrhythmias: irregular heart rhythms requiring immediate care.
• Syncope: sudden loss of consciousness.
• Allergic reaction: rash, itching, or anaphylaxis.
• Methemoglobinemia: abnormal hemoglobin causing reduced oxygen delivery.

Before using Isoket, clinicians should consider several safety measures.

• Monitor blood pressure: avoid excessive hypotension, especially in volume‑depleted patients.
• Avoid concurrent use with phosphodiesterase‑5 inhibitors: risk of profound hypotension.
• Use with caution in patients with severe anemia: nitrates may exacerbate tissue hypoxia.
• Assess for nitrate tolerance: consider nitrate‑free intervals to maintain efficacy.
• Store at below 25°C: keep in the original container, protect from light and moisture.

Isoket can interact with several drug classes; awareness of these interactions helps prevent adverse events.

Major Interactions (Avoid)

• Sildenafil, tadalafil, and other PDE5 inhibitors: may cause severe hypotension.
• Other nitrates (e.g., nitroglycerin): additive vasodilatory effect leading to dangerous blood pressure drops.
• Sodium nitrite: increased nitrite levels can precipitate methemoglobinemia.

Moderate Interactions (Monitor Closely)

• Antihypertensives such as ACE inhibitors or beta‑blockers: additive blood pressure lowering.
• Diuretics: may enhance hypotensive response.
• Alcohol: can increase vasodilatory effects and dizziness.